High chocolate content (27 per cent) but they are more sugary than the rest. (One biscuit contains the equivalent of one rounded teaspoon). A plus point is that they are 25 per cent lower in salt than other varieties. 2/5

Second healthiest choice, with moderate fat and calorie counts. But there's no information on salt content, so it's hard to know how healthy a choice it really is. 3/5

Verdict: For what appear to be identical sandwiches, there is a huge variation in their nutritional value. Best is to go for the nonmayonnaise variety, but of the standard ranges, Marks & Spencer comes out best.Winner: Marks & Spencer